Speaking outside the high court, Hallam – who was put in prison at the age of 17 and released only on Wednesday – said he had not received an apology from the police for wrongly focusing on him as one of the killers of Essayas Kassahun in a gang attack in Hoxton, north London, in 2004.

"It [the investigation] just wasn't done properly," he said.

"Them not doing their job properly cost me eight years of my life. I lost eight years of my life and nothing is going to happen to them."

The court of appeal quashed his 2005 conviction for murder on Thursday after hearing that evidence he had had all along on his own mobile phone undermined the case against him.

The phone was never examined by the Metropolitan police investigating the murder of Kassahun, nor by Hallam's own defence team, nor raised as an issue by him – which Lady Justice Hallett blamed on his own "faulty recollection and dysfunctional lifestyle".

Hallam, who is now 24, said on Thursday that prison had been tough. He started his sentence in Feltham young offenders' institution – which his uncle, Terry Hallam, said had been very difficult.

His father killed himself while Hallam was in prison, and he has not yet been able to visit his grave. "Just knowing I was innocent and having a lot of support outside kept me going," Hallam said on Thursday in an interview with BBC London. "I couldn't have done it personally, it was the support outside."

Clearly angry with the police, he said: "I have lost my family, my family lost me, I have lost my life. I spent all my time in prison, and I lost my liberty … I can't get that back. That time is gone. I have got to carry on from there."

He thanked his family and the huge numbers of supporters from the community in Hoxton for their long campaign to free him.

Hallam was jailed in 2005 for life with the recommendation that he serve at least 12 years for the murder of Kassahun, having served a year on remand at 17.

The main evidence against him was from two young witnesses whom the appeal court said on Thursday had only a fleeting glimpse of what happened and for whom there was always plenty of scope for making a mistaken identification.

His case was investigated by the Criminal Cases Review Commission, which brought an appeal based on fresh evidence that raised doubts about the reliability of the two key witnesses and new information from his mobile phone in the form of pictures that supported what he had always maintained: that he had not been at the scene at the time Kassahun was killed.

Hallam was released on bail on Wednesday when the crown surprisingly announced that it would not oppose his appeal. He is one of the youngest victims of a miscarriage of justice. His freedom had come after a massive campaign was launched – eliciting the support of the actor Ray Winstone among others – to clear his name.

But in her ruling on Thursday, Hallett said what had emerged was that Hallam had evidence in his possession – his mobile phone – that could have helped him all along. When he was arrested, Hallam could not remember where he was on the night of the murder. He later said he was with a friend – Timothy Harrington – but Harrington denied being with him, and the crown claimed at the trial that Hallam had clearly made up an alibi.

Hallam remained silent when he was arrested by the police shortly after the killing in 2004.

"It has to be said that his inability two days after to say where he was at the time of the murder has not exactly helped his case," Hallett said. She asked why neither the police nor his legal team had examined his two mobile phones

"One reason proffered for the failure to examine the phones was that in 2004 the Metropolitan police did not have the technology in use for 3G phones," she said.

"However, given our limited knowledge, we would have thought that even a cursory check would have produced some interesting results."

When Hallam's 3G phone was eventually examined by the CCRC and Thames Valley police – which carried out inquiries for the CCRC – it was found to contain pictures that put Hallam in a pub with his father on the evening of the killing and also showed that he had been with Harrington the day after – thereby giving credence to his original alibi.

It raised the distinct possibility, the judge said, that Hallam and his friend Harrington had merely been mistaken as to when they had met and that he had not – as was claimed – concocted an alibi.

Expressing surprise that Hallam himself had not mentioned the existence of his phone or the fact that he had been taking pictures with it to his legal team, she said: "We would have thought the appellant [Hallam] would have alerted the defence team that he had been taking photos on a new phone, which would have helped establish his whereabouts."

She blamed his failure to alert them on his "faulty recollection and a dysfunctional lifestyle, not a deliberate lie".

Hallett stopped short of criticising the Met or the Crown Prosecution Service, which were accused by Hallam's defence team at his appeal of failing to pursue lines of inquiry and not disclosing all the evidence.

Quashing his murder conviction, Hallett said there was now significant material before the court that supported Hallam's story that he was not at the scene of the murder on the night.

"The situation has now changed dramatically," said Hallett. The "false alibi" claim that the prosecution had used to support their two witnesses had now been "significantly undermined".

The Met police said: "The death of Essayas Kassahun was a tragedy and what followed was a complex investigation for which one person remains convicted. It is a matter of deep regret that Sam Hallam lost his liberty due to what has subsequently been found to be an unsafe conviction. The circumstances of his death involved a large group of people and this type of investigation often relies on people coming forward to give us personal accounts. We continue to face challenging investigations such as these and there are undoubtedly certain lessons to be learned for police and the wider criminal justice system from today's judgement which we will carefully consider."